Implements for distributing agricultural product (e.g. seed, fertilizer, etc.) in a field are generally towed behind a tractor or other vehicle. Such implements include one or more ground engaging tools for opening the ground to provide a path in which the agricultural product is deposited. Deposition is accomplished by a system for distributing the agricultural product generally from a single large bin through various lines and ports to be finally deposited on the ground through an outlet port. Following the deposition of the agricultural product, packers cover the deposited agricultural product with soil.
An air cart is one system for distributing agricultural product. An air cart comprises one or more large bins for holding one or more different types of agricultural product, an airflow source (e.g. a fan) and lines or hoses through which agricultural product is carried by the airflow to outlets located at or near the ground engaging tools of the implement. The product passes through the outlet to be deposited on the ground. There are typically a plurality of lines, hoses and ports, one outlet port associated with each ground engaging tool in order to apply product in a regular pattern to large areas of land in a single pass of the implement.
In air carts, proper metering of agricultural product into the airflow is desired to regularize the amount of product delivered to the outlets over time in order to reduce over- or under-deposition of the product in a particular area. Air carts traditionally employed single auger hoppers in which one very large (1-2 feet long) rotating auger distributed agricultural product from the hopper into a single airstream. Such arrangements are still used today by some manufacturers, for example Amity. Single auger air carts suffer from a number of problems. First, either the auger is on or off so agricultural product is either delivered across the entire implement or not delivered at all anywhere on the implement. Thus, fine control over sectional metering is impossible. Second, agricultural product must be metered into an initial large 5″ line, and then split into 2.5″ lines followed by another split into 1″ lines. This creates more complexity as secondary splitters are required and provides less control in how product is transported around the distribution system. Third, it is impossible to distribute more than one kind of product at the same time.
Fine sectional control is desirable because passage of the implement over soil that has already received agricultural product (e.g. the headland) would result in waste of product; therefore, it is desirable to shout off distribution to parts of the implement that are passing over such soil. In an effort to solve this problem, metering apparatuses are preferably equipped with sectional shutoff capabilities to selectively stop deposition of product at parts of the implement passing over already serviced soil. Metering apparatuses for this purpose are known in the art, for example as disclosed in US 2012/0325131 published Dec. 27, 2012, U.S. Pat. No. 8,132,521 issued Mar. 13, 2012, U.S. Pat. No. 8,141,504 issued Mar. 27, 2012 and U.S. Pat. No. 8,196,534 issued Jun. 12, 2012, the entire contents of all of which are herein incorporated by reference. Such metering apparatuses generally involve a meter roller assembly in which a plurality of meter rollers is rotated on a common shaft, the rollers rotating around a transverse axis relative to the motion of the distribution implement. In such an arrangement, sectional control of the meter rollers to prevent distribution of product to certain parts of the implement is problematic. Complicated clutching mechanisms or inefficient gating mechanisms have all been used as described in the aforementioned prior art apparatuses.
Recent developments have provided metering apparatuses for distributing an agricultural product having a plurality of metering elements coupled to a drive input, each of the metering elements rotating around different axes of rotation. Examples are described in commonly owned U.S. Ser. No. 14/198,584 filed Mar. 5, 2014 and in U.S. Pat. No. 8,434,416 issued May 7, 2013, the entire contents of both of which are herein incorporated by reference. Sectional control may be accomplished by shutting off flow of agricultural product at individual metering elements through the use of clutches or individually driven metering elements.
However, there remains a need for metering apparatuses for agricultural product having different means for sectional control of product distribution in a field.